This invention relates to a method and apparatus for the control of an air conditioner used in a process of treating air in a compartment to regulate its temperature. While the general principles and teachings hereinafter disclosed are applicable to all air conditioners, the invention is hereinafter described in detail in connection with its application to an air conditioner for use in automotive vehicles.
There has been developed a type of air conditioner having a motor-driven blower for creating air flow through an air passage which opens into a compartment through a plurality of outlets. Each of these outlets is controlled to selectively block or permit air flow through it into the compartment as required during an air-blowing mode. For example, a selected one of the outlets opens to permit air flow through it into the compartment upon a requirement for single-flow mode such as "vent" mode, whereas a selected pair of the outlets open to permit air flow through them into the compartment upon a requirement for dual-flow mode such as "heat" mode and "bi-level" mode.
It is the normal practice to control the voltage to the blower-motor, which determines the rate of air flow through the air passage, based upon a difference between actual and target values for compartment temperature without accounting for a change between single- and dual-flow modes. That is, the voltage to the blower-motor remains unchanged upon a change between single- and dual-flow modes. This causes a change in the rate of air flow to the compartment through each outlet. Such an air flow rate change cause the user discomfort.
Therefore, the present invention provides an improved method and apparatus for the control of an air conditioner which can maintain the blowing-air flow rate unchanged upon a change of the air-blowing mode and which can enhance passenger comfort.